The present invention relates to an optical measuring device, and more particularly, to a temperature varying arrangement for measuring temperatures using a material having a property whereby the amount of light transmitted therethrough varies with temperature.
FIG. 1 shows a conventional temperature measuring device employing light. Designated at 1 is a light source, 2 an optical fiber, 3 a material having a property whereby the amount of light transmitted therethrough varies as a function of temperature, 4 a light detector, 5 a signal processor, 6 a display, and 1a a constant-temperature container surrounding the light source 1.
Light emitted from the light source 1 is guided by the optical fiber 2 to the temperature-measuring material 3. The light passes through the material 3 in an amount depending on the temperature, and then passes through the optical fiber 2 to the light detector 4. the light detector 4 converts the detected light to an electrical quantity, which is processed by the signal processor 5 to derive the temperature, which is then displayed on the display 6.
The temperature of the light source 1 is stabilized by the constant-temperature container 1a surrounding the light source 1. This is necesary because the wavelength of the light emitted from the light source 1 is generally affected by the temperature of the light source 1, resulting in an error in temperature measurement if the ambient temperature were to change.
Hence, the conventional temperature device requires the constant-temperature container 1a because the wavelength of the light source 1 has to be stabilized. Therefore, the device is expensive to construct and is large in size.